Sheet metal bending brake

ABSTRACT

A sheet metal bending brake includes a frame having both a stationary portion as well as a clamping jaw. The stationary portion is adapted to support a piece of sheet metal on a planar support surface while the clamping jaw is movably mounted relative to the stationary portion of the frame to selectively clamp a piece of sheet metal between the clamping jaw and the stationary portion of the frame. An elongated bending arm is pivotally mounted to the frame about a first axis and movable between a first and a second position. An elongated sleeve is pivotally mounted to the bending arm about a second axis which is parallel to but spaced from the first axis. The bending sleeve and frame each have coacting surfaces so that the sleeve automatically pivots between a first and second position relative to the bending arm as the bending arm is pivoted between its first and second position relative to the frame during a bending operation.

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority of U.S. Provisional Patent Application Serial No. 60/331,670 filed Nov. 19, 2001, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

[0002] I. Field of the Invention

[0003] The present invention relates to sheet metal bending brakes.

[0004] II. Description of the Prior Art

[0005] There are many previously known sheet metal bending brakes which are used primarily in the aluminum siding business. These sheet metal bending brakes typically comprise a frame having an elongated support portion on which a piece of sheet metal to be bent is positioned. An elongated clamping jaw is selectively movable between a clamping position and a release position relative to the frame. In its clamping position, the clamping jaw sandwiches the piece of sheet metal to be bent in between the clamping jaw and the frame. Furthermore, with the sheet metal sandwiched in between the clamping member and the frame, a portion of the sheet metal to be bent extends outwardly from an elongated edge on the clamping member and an elongated edge of the frame so that the portion of the sheet metal to be bent protrudes outwardly from the clamping jaw.

[0006] With the sheet metal clamped to the frame, an elongated bending arm assembly is pivotally mounted to the frame and movable from a first and to a second position. Upon pivoting, the bending assembly engages the sheet metal clamped between the clamping jaw and frame and bends the outwardly protruding portion of the sheet metal in the desired fashion.

[0007] There have been previously known special hinges for securing the bending arm assembly to the frame and which are particularly designed to minimize scuffing or other marring of the sheet metal as it is bent by the bending brake. One such previously known hinge is disclosed in U.S. Pat. No. 4,557,132 which issued on Dec. 10, 1985.

[0008] One disadvantage of these previously known sheet metal bending brakes, however, is that they are unable to make relatively narrow bends in the sheet metal, i.e. a bend in which the outwardly protruding portion of the clamped sheet metal is three-eighths of an inch or less. Rather, operation of these previously known sheet metal bending brakes with relatively narrow bends causes the hinge to crush the sheet metal against the bending arm assembly rather than to perform the sharp bend as desired.

SUMMARY OF THE PRESENT INVENTION

[0009] The present invention provides a sheet metal bending brake which overcomes all of the above-mentioned disadvantages of the previously known devices.

[0010] In brief, the sheet metal bending brake of the present invention comprises a frame having an elongated surface adapted to support a piece of sheet metal to be bent. A clamping jaw is movably mounted to the frame and movable between a clamped and released position. In its clamped position, the clamping jaw sandwiches the piece of sheet metal between the clamping jaw and the frame so that a portion of the sheet metal to be bent protrudes outwardly from an elongated edge of the clamping jaw.

[0011] An elongated bending arm is pivotally mounted to the frame about a first axis and movable between a first and a second position. The first axis, furthermore, is parallel to the elongated edge on the clamping jaw.

[0012] An elongated sleeve is pivotally mounted to the bending arm about a second axis which is parallel to but spaced outwardly from the first axis. Furthermore, the bending sleeve and the frame each have coacting surfaces so that said sleeve automatically pivots between a first and second position relative to the bending arm as the bending arm is pivoted between its first and second positions during a bending operation. As such, the bending sleeve maintains constant contact with the outwardly protruding portion of the sheet metal to be bent even when this outwardly protruding portion is very small, e.g. less than three-eighths of an inch.

BRIEF DESCRIPTION OF THE DRAWING

[0013] A better understanding of the present invention will be had upon reference to the following detailed description, when read in conjunction with the accompanying drawing, wherein like reference characters refer to like parts throughout the several views, and in which:

[0014]FIG. 1 is an elevational view illustrating a preferred embodiment of the invention;

[0015]FIG. 2 is a fragmentary view of a portion of the preferred embodiment of the invention; and

[0016] FIGS. 3-8 are all fragmentary end views illustrating the operation of the present invention.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT OF THE PRESENT INVENTION

[0017] With reference now to FIGS. 1 and 3, a preferred embodiment of the sheet metal bending brake 10 of the present invention is shown and comprises a rigid frame 12 having an elongated support surface 14. The support surface 14 is adapted to support a piece of sheet metal 15 to be bent.

[0018] Still referring to FIGS. 1 and 3, an elongated clamping jaw 16 having an elongated edge 18 is movably mounted to the frame between a clamped position, illustrated in solid line in FIG. 3, and a release position, illustrated in phantom line in FIG. 3. In its clamped position, the clamping jaw 16 sandwiches the sheet metal 15 in between the clamping jaw 16 and the support surface 14 of the frame 12 so that a portion 36 of the sheet metal 15 protrudes outwardly from the elongated edge 18 of the clamping jaw 16. Typically, the portion 36 of the sheet metal protruding outwardly from the edge 18 of the clamping jaw 16 will range between a quarter of an inch and several inches. Furthermore, the clamping jaw 16 is mounted to the frame so that the clamping jaw edge 18 is parallel to an edge 19 on the frame 12 along the support surface 14.

[0019] Any conventional means may be used to move the clamping jaw 16 from its release position (phantom line in FIG. 3) and its clamped position (solid line in FIG. 3). For example, a conventional cam lock or snap lock 21 (FIG. 1) may be used to move the clamping jaw relative to the frame.

[0020] With reference now to FIGS. 2 and 3, an elongated bending arm assembly 20 is pivotally secured to the frame about a pivot axis 22 which is parallel to the edge 18 of the clamping jaw 16. Preferably, this axis 22 is positioned closely adjacent the edge 18 of the clamping jaw 16 and immediately below it.

[0021] In a fashion which will subsequently be described in greater detail, the bending bar assembly 20 is pivotal from a first position, illustrated in FIG. 3, prior to the sheet metal bend and to a second final bending position, illustrated in FIG. 8, at the end of the sheet metal bend. In its second final bending position, the portion 36 of the sheet metal 15 protruding outwardly from the clamping jaw edge 18 is bent against an upper surface of the clamping jaw 16.

[0022] With reference now particularly to FIGS. 2 and 3, the bending arm assembly 20 includes both a bending arm 30 which is pivotally secured to the frame 12 about the pivot axis 22. This pivot axis 22, furthermore, is parallel to and spaced downwardly from the edge 18 of the clamping member 16.

[0023] The bending arm assembly 20 further includes an elongated sleeve 50, preferably constructed of plastic, which is pivotally secured to the bending arm 30 about a pivot axis 52 which is parallel to but spaced from the pivot axis 22. Although any conventional pivotal connection may be utilized between the sleeve 50 and the bending arm 30, in the preferred embodiment the sleeve 50 includes an extruded channel 54 which is slidably disposed over a rail 56 formed on the bending arm 30.

[0024] The sleeve 50 is pivotal relative to the bending arm 30 between a first position at the initiation of a bend, as illustrated in FIG. 3, and a second position at the conclusion of the bend as illustrated in FIG. 8. Furthermore, during a sheet metal bend, i.e. as the bending arm 30 is pivoted from its first to its second position as shown in FIGS. 4-8, an elongated planar portion 60 of the sleeve 50 engages and bends the outwardly protruding portion 36 of the sheet metal 15 in the desired fashion.

[0025] With reference now particularly to FIG. 3, at the initiation of a bend, i.e. when both the bending arm 30 and sleeve 50 are in their respective first positions, the planar portion 60 of the sleeve 50 is generally aligned with the sheet metal support surface 14 of the frame 12. Furthermore, as shown in FIGS. 2 and 4, at the initiation of the bend, a free end 66 of the sleeve 50 coacts with an outwardly protruding ledge 68 on the frame so that this coaction between the surfaces 66 and 68 limits the pivotal action of the sleeve 50 relative to the bending arm 30.

[0026] As the bending arm 30 is moved from its initial or first position (FIG. 3) to an intermediate bending position (FIGS. 4-6), the force exerted by the portion 36 of the sheet metal 22 against sleeve planar portion 60 maintains the contact between the surfaces 66 and 68 on the sleeve 50 and frame 12, respectively. During this period, the sleeve 50 pivots outwardly relative to the bending arm 30. However, at the intermediate position (FIG. 7) the sleeve 50 disengages from the ledge surface 68 so that the pivotal position of the sleeve 50 is limited by its engagement with the bending arm 30. Thus, as the bending assembly 50 is rotated from its intermediate position (FIG. 7) to its final or second bending position (FIG. 8), the pivotal position of the sleeve 50 relative to the bending arm 30 remains fixed.

[0027] Although the operation of the bending brake 10 of the present invention should by now be clear, a summation of its operation is as follows. First, the sheet metal 15 to be bent is positioned on the frame support surface 14 so that a portion 36 protrudes outwardly from the support portion 14. When properly positioned, the clamping jaw 16 is moved to its clamped position thus sandwiching the sheet metal 15 in between the clamping jaw 16 and frame support surface 14 against movement. At the same time, bending arm assembly 20 is in its first position illustrated in FIG. 3.

[0028] Thereafter, as the bending arm assembly 20 is moved from its first position (FIG. 3) and towards the second position (FIGS. 4-8), the planar portion 60 of the sleeve 50 engages the portion 36 of the sheet metal and bends the sheet metal portion 35 in the desired fashion against the upper surface 65 of the clamping jaw 16. Furthermore, during substantially one-half of the bend performed by the bending arm assembly 20, the sleeve 50 pivots from its first and to its second position relative to the bending arm 30. Conversely, during approximately the second half of the bend, the position of the sleeve 50 remains fixed relative to the bending arm 30.

[0029] If a hem is desired following the initial bend, the bent sheet metal 15 can be removed from between the clamping jaw 16 and frame 12 and positioned along the top of the clamping jaw 16 adjacent its free edge 18. Thereafter, the bending arm assembly is moved from its first and to its second position thus performing the hem.

[0030] A primary advantage of the sheet metal bending brake of the present invention is that sheet metal bends and hems can be performed where the outwardly protruding portion 36 of the sheet metal is relatively small, i.e. less than three-eighths of an inch. Furthermore, since the sleeve 50 is preferably constructed of plastic, marring of the sheet metal during the bending operation is avoided.

[0031] Having described my invention, many modifications thereto will become apparent to those skilled in the art to which it pertains without deviation from the spirit of the invention as defined by the scope of the appended claims.

[0032] I claim: 

1. A sheet metal bending brake comprising: a frame adapted to support a piece of sheet metal, a clamping jaw movable relative to the frame to clamp the sheet metal between the clamping jaw and the frame, an elongated bending arm pivotally mounted to said frame about a first axis and movable between a first and second position, an elongated sleeve pivotally mounted to said bending arm about a second axis parallel to and spaced from said first axis, said bending sleeve and said frame having coacting surfaces so that said sleeve automatically pivots between a first and second position relative to said bending arm as said bending arm is pivoted between its first and second position relative to said frame.
 2. The invention as defined in claim 1 wherein said sleeve is made of plastic.
 3. The invention as defined in claim 1 wherein said frame comprises an elongated edge parallel to said first axis.
 4. The invention as defined in claim 3 wherein said frame comprises a ledge protruding outwardly from said edge, said ledge forming said coacting surface on said frame.
 5. The invention as defined in claim 4 wherein said second axis is spaced outwardly from a free edge of said ledge.
 6. The invention as defined in claim 5 wherein said sleeve comprises a portion extending from said second axis toward said frame edge, said coacting surface on said sleeve being positioned adjacent a free edge of said sleeve.
 7. The invention as defined in claim 6 wherein said sleeve portion is dimensioned so that said coacting surfaces on said frame and said sleeve separate from each other at an intermediate position between said first and second positions of said bending arm. 